* Poll showed sharply lower winning margin a day earlier
* Parliamentary election due on June 12
(Adds second poll)
ISTANBUL, June 1 (Reuters) - Turkey’s ruling AK Party is on course for a third consecutive election win on June 12, with support at around 50 percent, according to surveys published on Wednesday.
A survey by pollsters Konsensus published in Haberturk newspaper put support for Prime Minister Tayyip Erdogan’s party at 48.6 percent, which would mark an increase from the near 47 percent which it achieved in the 2007 vote.
A separate survey by Sonar showed support for AK Party at 50.93 percent, according to the polling company’s website.
A day earlier a survey by lesser known polling company DORInsight had shown support for Erdogan’s party at 39 percent, well below the 45-50 percent level recorded by better known pollsters.
The success of the AK Party, an economically liberal but socially conservative party, has been driven by strong economic growth in near nine years in power.
The Konsensus poll was conducted between May 18-28 and based on 3,000 voters. The published details did not include a margin of error or specify how many provinces the voters came from.
Support for the opposition Republican People’s Party (CHP), which is under new leadership, was at 28.3 percent of the vote and the Nationalist Movement Party (MHP) at 11.6 percent, above the 10 percent threshold needed for a party to enter parliament.
Sonar’s poll was conducted between May 24-31 and based on 3,000 voters. The published details did not include a margin of error, but it said the voters came from 39 provinces.
CHP support was seen at 25.78 percent and MHP at 12.45 percent, Sonar said.
The polls suggested there had been little impact for the ultra-nationalist MHP from a sex video scandal which led to the resignation of 10 leading party members.
If his party wins a strong mandate, Erdogan has promised to overhaul Turkey’s constitution, written in the 1980s after a coup. However, the latest poll indicated it would not have the two-thirds majority in parliament needed to change the constitution without going to a referendum. (Writing by Daren Butler and Seda Sezer; editing by Elizabeth Piper)